Opus1 icon Opus2 icon

Frequently Asked Questions

Welcome to Circle of 5ths!

Getting started with Opus 1

Rotate the circle with your finger. The selected key is highlighted in red. The outer key circle shows major keys (in capital letters) and the inner circle shows their relative minor keys (in lowercase). The outer roman numeral ring represents chords that are commonly used in the selected major key. The inner roman numeral ring represents common chords in the selected minor key.

The roman numeral corresponds to the note in the selected key's scale. So in the key of C Major, roman numeral "one" (Ⅰ) means the base of the chord is the first note of the key's scale, so it's a C chord.

The scale and chord progression shown above the circle correspond with the selected key and the part of the circle that's in color.

Tap on the small red button next to the chord staff to switch between roman numerals and chord names.

Tap on the scale or a chord to play it out loud.

Getting started with Opus 2

Circle of 5ths, Opus 2 is an advanced version of Opus 1 that includes musical modes. A mode is a type of scale and there are seven modes, including the more common major scale (Ionian mode) and minor scale (Aeolian mode). Similar to Opus 1, you can rotate the circle to explore keys. Tap a note in the scale or tap a chord to play it out loud, and you can tap the play buttons to play out the entire scale or chord progression. Switch musical modes by tapping on the key name in the top left corner of the screen.

Chord Symbol Notation

C = C Major chord

Cm = c minor chord

C° = c diminished chord

Examples of Music in Different Modes

Jazz can be in a range of musical modes; Dorian mode is popular for jazz and blues. Phrygian mode is commonly used in Flamenco music. Eastern European music, particular klezmer, uses Dorian mode. The theme for The Simpsons is in Lydian mode. Locrian mode is rarely used, but Björk uses it in the bass line for "Army of Me." Dolly Parton’s Jolene lick is in Dorian mode.

Accessibility and VoiceOver

Circle of Fifths is equipped with accessibility features. With VoiceOver activated, use three-finger swipe to change keys. Swipe vertically to switch from a major key to its relative minor.

How do I contact you?

For Circle of 5ths, Opus 1, email us at 5ths@felttip.com.
For Circle of 5ths, Opus 2, email us at 5ths- opus2@felttip.com.